From: Kees Cook <keescook@chromium.org>
To: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
linux-kernel <linux-kernel@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Alexander Potapenko <glider@google.com>,
Joe Perches <joe@perches.com>, Andy Whitcroft <apw@canonical.com>,
"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
<x86@kernel.org>,
drbd-dev@lists.linbit.com, linux-block@vger.kernel.org,
b43-dev@lists.infradead.org,
Network Development <netdev@vger.kernel.org>,
linux-wireless <linux-wireless@vger.kernel.org>,
linux-ide@vger.kernel.org, linux-clk@vger.kernel.org,
linux-spi@vger.kernel.org, Linux-MM <linux-mm@kvack.org>,
clang-built-linux <clang-built-linux@googlegroups.com>
Subject: Re: [PATCH 01/10] x86/mm/numa: Remove uninitialized_var() usage
Date: Thu, 4 Jun 2020 07:56:40 -0700 [thread overview]
Message-ID: <202006040745.525ECD1@keescook> (raw)
In-Reply-To: <CANiq72kLqvriYmMkdD3yU+xJwbn-68Eiu-fTNtC+Lb+1ZRM75g@mail.gmail.com>
On Thu, Jun 04, 2020 at 01:41:07PM +0200, Miguel Ojeda wrote:
> On Thu, Jun 4, 2020 at 9:58 AM Thomas Gleixner <tglx@linutronix.de> wrote:
> >
> > but if we ever lose the 1 then the above will silently compile the code
> > within the IS_ENABLED() section out.
>
> Yeah, I believe `IS_ENABLED()` is only meant for Kconfig symbols, not
> macro defs in general. A better option would be `__is_defined()` which
> works for defined-to-nothing too.
Er? That's not what it looked like to me:
#define IS_BUILTIN(option) __is_defined(option)
#define IS_ENABLED(option) __or(IS_BUILTIN(option), IS_MODULE(option))
But just to be sure, I just tested in with a real build:
[ 3.242160] IS_ENABLED(TEST_UNDEF) false
[ 3.242691] __is_defined(TEST_UNDEF) false
[ 3.243240] IS_ENABLED(TEST_VALUE_EMPTY) false
[ 3.243794] __is_defined(TEST_VALUE_EMPTY) false
[ 3.244353] IS_ENABLED(TEST_VALUE_1) true
[ 3.244848] __is_defined(TEST_VALUE_1) true
and nope, it only works with a defined value present.
diff --git a/init/main.c b/init/main.c
index 03371976d387..378a9e54b6dc 100644
--- a/init/main.c
+++ b/init/main.c
@@ -1406,6 +1406,34 @@ static int __ref kernel_init(void *unused)
*/
pti_finalize();
+#undef TEST_UNDEF
+ if (IS_ENABLED(TEST_UNDEF))
+ pr_info("IS_ENABLED(TEST_UNDEF) true\n");
+ else
+ pr_info("IS_ENABLED(TEST_UNDEF) false\n");
+ if (__is_defined(TEST_UNDEF))
+ pr_info("__is_defined(TEST_UNDEF) true\n");
+ else
+ pr_info("__is_defined(TEST_UNDEF) false\n");
+#define TEST_VALUE_EMPTY
+ if (IS_ENABLED(TEST_VALUE_EMPTY))
+ pr_info("IS_ENABLED(TEST_VALUE_EMPTY) true\n");
+ else
+ pr_info("IS_ENABLED(TEST_VALUE_EMPTY) false\n");
+ if (__is_defined(TEST_VALUE_EMPTY))
+ pr_info("__is_defined(TEST_VALUE_EMPTY) true\n");
+ else
+ pr_info("__is_defined(TEST_VALUE_EMPTY) false\n");
+#define TEST_VALUE_1 1
+ if (IS_ENABLED(TEST_VALUE_1))
+ pr_info("IS_ENABLED(TEST_VALUE_1) true\n");
+ else
+ pr_info("IS_ENABLED(TEST_VALUE_1) false\n");
+ if (__is_defined(TEST_VALUE_1))
+ pr_info("__is_defined(TEST_VALUE_1) true\n");
+ else
+ pr_info("__is_defined(TEST_VALUE_1) false\n");
+
system_state = SYSTEM_RUNNING;
numa_default_policy();
which means a few other __is_defined() users are not correct too...
--
Kees Cook
next prev parent reply other threads:[~2020-06-04 14:56 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-03 23:31 [PATCH 00/10] Remove uninitialized_var() macro Kees Cook
2020-06-03 23:31 ` [PATCH 01/10] x86/mm/numa: Remove uninitialized_var() usage Kees Cook
2020-06-04 7:58 ` Thomas Gleixner
2020-06-04 11:41 ` Miguel Ojeda
2020-06-04 14:56 ` Kees Cook [this message]
2020-06-04 15:22 ` Miguel Ojeda
2020-06-04 14:34 ` Kees Cook
2020-06-04 21:39 ` Thomas Gleixner
2020-06-04 22:39 ` Kees Cook
2020-06-03 23:31 ` [PATCH 02/10] drbd: " Kees Cook
2020-06-04 19:56 ` Nick Desaulniers
2020-06-03 23:31 ` [PATCH 03/10] b43: " Kees Cook
2020-06-04 20:08 ` Nick Desaulniers
2020-06-04 20:18 ` Kees Cook
2020-06-04 20:25 ` Nick Desaulniers
2020-06-05 9:20 ` Kalle Valo
2020-06-03 23:31 ` [PATCH 04/10] rtlwifi: rtl8192cu: " Kees Cook
2020-06-04 20:16 ` Nick Desaulniers
2020-06-05 9:18 ` Kalle Valo
2020-06-03 23:31 ` [PATCH 05/10] ide: " Kees Cook
2020-06-04 19:29 ` Nick Desaulniers
2020-06-04 20:20 ` Kees Cook
2020-06-04 20:29 ` Nick Desaulniers
2020-06-15 19:32 ` Kees Cook
2020-06-04 20:58 ` Sedat Dilek
2020-06-03 23:31 ` [PATCH 06/10] clk: st: " Kees Cook
2020-06-04 4:38 ` Stephen Boyd
2020-06-03 23:32 ` [PATCH 07/10] spi: davinci: " Kees Cook
2020-06-04 19:40 ` Nick Desaulniers
2020-06-03 23:32 ` [PATCH 08/10] checkpatch: Remove awareness of uninitialized_var() macro Kees Cook
2020-06-04 0:02 ` Joe Perches
2020-06-04 1:40 ` Kees Cook
2020-06-04 1:47 ` Joe Perches
2020-06-04 2:44 ` Kees Cook
2020-06-04 2:53 ` Sedat Dilek
2020-06-04 3:46 ` Kees Cook
2020-06-03 23:32 ` [PATCH 09/10] treewide: Remove uninitialized_var() usage Kees Cook
2020-06-04 3:33 ` Nathan Chancellor
2020-06-04 4:02 ` Kees Cook
2020-06-04 10:45 ` Leon Romanovsky
2020-06-04 13:23 ` Jason Gunthorpe
2020-06-04 14:59 ` Kees Cook
2020-06-04 17:57 ` Jason Gunthorpe
2020-06-04 19:09 ` Geert Uytterhoeven
2020-06-05 9:25 ` Kalle Valo
2020-06-03 23:32 ` [PATCH 10/10] compiler: Remove uninitialized_var() macro Kees Cook
2020-06-04 0:00 ` Bart Van Assche
2020-06-04 0:50 ` Miguel Ojeda
2020-06-04 1:23 ` [PATCH 00/10] " Sedat Dilek
2020-06-04 1:44 ` Kees Cook
2020-06-04 1:46 ` Sedat Dilek
2020-06-04 3:33 ` Nathan Chancellor
2020-06-04 7:26 ` Sedat Dilek
2020-06-04 14:27 ` Kees Cook
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